Deep ultraviolet light photoresist processing

Abstract

Process for post exposure treatment of a latent image on a semiconductor wafer. After a deep ultraviolet (UV) photoresist has been exposed, the wafer, including the latent image in the attached photoresist, is maintained in an inert gas to protect the resist from the air atmosphere. Then the latent image is baked to stabilize the image.

We claim: 
     
       1. In a semiconductor fabrication process comprising the steps of: coating a wafer with photoresist, said photoresist producing a photoacid when irradiated with radiation of a predetermined range of wavelengths, said photoacid catalyzing a chemical reaction when said photoresist is baked to increase the solubility said photoresist in the non irradiated areas with respect to the a solubility of said photoresist in the non irradiated areas;   irradiating said photoresist on said wafer with said radiation of a predetermined wavelength to generate said photoacid defining a latent image in said photoresist on said wafer, said irradiating step following said coating step;   preventing said photoacid from being neutralized by maintaining said wafer coated with said photoresist containing said latent image in water; and   baking said latent image in photoresist on said wafer, said baking step following said preventing step.   
     
     
       2. The process as in claim 1, wherein said photoresist is a deep UV photoresist, said deep UV photoresist being responsive to radiation of a wavelength of 100-300 nm. 
     
     
       3. The process as in claim 1, wherein said photoresist is an I-line photoresist, said I-line photoresist being responsive to radiation of a wavelength of approximately 365 nm. 
     
     
       4. A process for forming a photoresist pattern comprising the steps of: coating a wafer with a photoresist, said photoresist producing a photoacid when irradiated with radiation of a predetermined range of wavelengths, said photoacid catalyzing a chemical reaction when said photoresist is baked to increase the solubility of said photoresist in the irradiated areas with respect to the solubility of said photoresist in the non irradiated areas;   irradiating said photoresist on said wafer with said radiation of a predetermined wavelength to generate said photoacid defining a latent image in said photoresist on said wafer, said irradiating step following said coating step;   preventing said photoacid from being neutralized by maintaining said wafer coated with said photoresist in a nitrogen atmosphere, said preventing step following said irradiating step; and   baking said latent image in said photoresist on said wafer, said baking step following said maintaining step.   
     
     
       5. The process as in claim 4, wherein said photoresist is a deep UV photoresist, said deep UV photoresist being responsive to radiation of a wavelength of 100-300 nm. 
     
     
       6. The process as in claim 4, wherein said photoresist is an I-line photoresist, said I-line photoresist being responsive to radiation of a wavelength of approximately 365 nm. 
     
     
       7. A process for forming a photoresist pattern comprising the steps of: coating a wafer with photoresist, said photoresist producing a photoacid when irradiated with radiation of a predetermined range of wavelengths, said photoacid catalyzing a chemical reaction when said photoresist is baked to increase the solubility of said photoresist in the non irradiated areas;   maintaining said wafer coated with said photoresist in a nitrogen atmosphere, said maintaining step following said coating step;   irradiating said photoresist on said wafer with said radiation of a predetermined wavelength to generate said photoacid defining a latent image in said photoresist on said wafer, wherein said irradiation occurs in said nitrogen atmosphere, said irradiating step following said coating step;   preventing said photoacid from being neutralized by maintaining said latent image in said photoresist on said wafer in said nitrogen atmosphere, said preventing step following said irradiating step; and   baking said latent image in said photoresist on said wafer, said baking step following said second maintaining step.   
     
     
       8. The process as in claim 7, wherein said photoresist is a deep UV photoresist, said deep UV photoresist being responsive to radiation of a wavelength of 100-300 nm. 
     
     
       9. The process as in claim 7, wherein said photoresist is an I-line photoresist, said I-line photoresist being responsive lo radiation of a wavelength of approximately 365 nm.